1. Field of the Invention
The present invention relates to a technology configured to identify the pixel position of a display panel of active matrix drive type in a short time. It should be noted that the present invention has a mode as both a display panel and a panel inspection apparatus.
2. Description of the Related Art
Recently, various types of display technologies have been proposed as FPDs (Flat Panel Displays). For example, these display technologies include non-self-illuminating display technologies, such as LCD (Liquid Crystal Display), that use backlighting and self-illuminating display technologies, such as plasma display and organic EL (Electro Luminescence) display.
The flat panel displays are based on the passive matrix driving and the active matrix driving. Recently, the active matrix driving has gained the mainstream.
The following describes the existing structure and technological problems of a pixel circuit based on the active matrix driving by uses of an organic EL display for an example.
Referring to FIG. 1, there is shown a top view of an exemplary configuration of a pixel circuit. It should be noted that FIG. 1 shows a pattern example in which one pixel is composed of three sub pixels. These three sub pixels are the three primary colors; R (Red), G (Green), and Blue (Blue).
As shown in FIG. 1, a pixel control line 1 is arranged so as to cross two or more sub pixels and a video signal line 3 corresponding to each sub pixel is arranged so as to orthogonally cross the pixel control line 1. In addition, a thin-film transistor is arranged in each sub pixel circuit, the thin-film transistor being connected to the pixel control line 1 and the video signal line 3. It should be noted that the configuration itself in each pixel circuit is known.
With today's display apparatuses, the display area is getting larger and the display resolution is getting increasingly finer, thereby necessarily making the pixel pitch increasingly narrower. This situation raises the probability of the occurrence of defects, such as the broken wires due to dust or the like during manufacturing processes of display panels, the short-circuits between adjacent wires, and inter-layer short-circuits in wire cross sections, for example.
Especially, defects encountered in the forming of the wiring in semiconductor transistors, for example, are fatal. Hence, electrical inspections have to be executed after each thin-film transistor film forming process to detect failing points and repair the detected failures.
For the above-mentioned purpose, various electrical inspection methods have been proposed (Japanese Patent Laid-Open No. 2004-102260, Japanese Patent Laid-Open No. 2004-347749, and Japanese Patent Laid-Open No. 2003-50380).